Take Tim's work on file.truncate out of 2.2.1 again.

Doc/lib/libstdtypes.tex

@@ -1152,15 +1152,11 @@ Files have the following methods:
 \end{methoddesc}
 
 \begin{methoddesc}[file]{truncate}{\optional{size}}
-  Truncate the file's size.  If the optional \var{size} argument is
+  Truncate the file's size.  If the optional \var{size} argument
   present, the file is truncated to (at most) that size.  The size
-  defaults to the current position.  The current file position is
-  not changed.  Note that if a specified size exceeds the file's
-  current size, the result is platform-dependent:  possibilities
-  include that file may remain unchanged, increase to the specified
-  size as if zero-filled, or increase to the specified size with
-  undefined new content.
-  Availability:  Windows, many \UNIX variants.
+  defaults to the current position.  Availability of this function
+  depends on the operating system version (for example, not all
+  \UNIX{} versions support this operation).
 \end{methoddesc}
 
 \begin{methoddesc}[file]{write}{str}

Lib/test/test_largefile.py

@@ -128,35 +128,20 @@ expect(os.lseek(f.fileno(), size, 0), size)
 expect(f.read(1), 'a') # the 'a' that was written at the end of the file above
 f.close()
 
-if hasattr(f, 'truncate'):
-    if test_support.verbose:
-        print 'try truncate'
-    f = open(name, 'r+b')
-    f.seek(0, 2)
-    expect(f.tell(), size+1)    # else we've lost track of the true size
-    # Cut it back via seek + truncate with no argument.
-    newsize = size - 10
-    f.seek(newsize)
-    f.truncate()
-    expect(f.tell(), newsize)   # else pointer moved
-    f.seek(0, 2)
-    expect(f.tell(), newsize)   # else wasn't truncated
-    # Ensure that truncate(smaller than true size) shrinks the file.
-    newsize -= 1
-    f.seek(42)
-    f.truncate(newsize)
-    expect(f.tell(), 42)        # else pointer moved
-    f.seek(0, 2)
-    expect(f.tell(), newsize)   # else wasn't truncated
-
-    # XXX truncate(larger than true size) is ill-defined across platforms
-
-    # cut it waaaaay back
-    f.seek(0)
-    f.truncate(1)
-    expect(f.tell(), 0)         # else pointer moved
-    expect(len(f.read()), 1)    # else wasn't truncated
 
-    f.close()
+# XXX add tests for truncate if it exists
+# XXX has truncate ever worked on Windows? specifically on WinNT I get:
+#     "IOError: [Errno 13] Permission denied"
+##try:
+##      newsize = size - 10
+##      f.seek(newsize)
+##      f.truncate()
+##      expect(f.tell(), newsize)
+##      newsize = newsize - 1
+##      f.seek(0)
+##      f.truncate(newsize)
+##      expect(f.tell(), newsize)
+##except AttributeError:
+##      pass
 
 os.unlink(name)

Misc/NEWS

@@ -27,11 +27,6 @@ Library
   arbitrary shell code can't be executed because a bogus URL was
   passed in.
 
-Windows
-
-- file.truncate([newsize]) now works on Windows for all newsize values.
-  It used to fail if newsize didn't fit in 32 bits, reflecting a
-  limitation of MS _chsize (which is no longer used).
 
 What's New in Python 2.2 final?
 Release date: 21-Dec-2001

Objects/fileobject.c

@@ -10,10 +10,8 @@
 
 #ifdef MS_WIN32
 #define fileno _fileno
-/* can simulate truncate with Win32 API functions; see file_truncate */
+/* can (almost fully) duplicate with _chsize, see file_truncate */
 #define HAVE_FTRUNCATE
-#define WINDOWS_LEAN_AND_MEAN
-#include <windows.h>
 #endif
 
 #ifdef macintosh
@@ -377,9 +375,6 @@ file_truncate(PyFileObject *f, PyObject *args)
 	newsizeobj = NULL;
 	if (!PyArg_ParseTuple(args, "|O:truncate", &newsizeobj))
 		return NULL;
-
-	/* Set newsize to current postion if newsizeobj NULL, else to the
-	   specified value. */
 	if (newsizeobj != NULL) {
 #if !defined(HAVE_LARGEFILE_SUPPORT)
 		newsize = PyInt_AsLong(newsizeobj);
@@ -390,80 +385,37 @@ file_truncate(PyFileObject *f, PyObject *args)
 #endif
 		if (PyErr_Occurred())
 			return NULL;
-	}
-	else {
-		/* Default to current position. */
+	} else {
+		/* Default to current position*/
 		Py_BEGIN_ALLOW_THREADS
 		errno = 0;
 		newsize = _portable_ftell(f->f_fp);
 		Py_END_ALLOW_THREADS
-		if (newsize == -1)
-			goto onioerror;
+		if (newsize == -1) {
+		        PyErr_SetFromErrno(PyExc_IOError);
+			clearerr(f->f_fp);
+			return NULL;
+		}
 	}
-
-	/* Flush the file. */
 	Py_BEGIN_ALLOW_THREADS
 	errno = 0;
 	ret = fflush(f->f_fp);
 	Py_END_ALLOW_THREADS
-	if (ret != 0)
-		goto onioerror;
+	if (ret != 0) goto onioerror;
 
 #ifdef MS_WIN32
-	/* MS _chsize doesn't work if newsize doesn't fit in 32 bits,
-	   so don't even try using it. */
-	{
-		Py_off_t current;	/* current file position */
-		HANDLE hFile;
-		int error;
-
-		/* current <- current file postion. */
-		if (newsizeobj == NULL)
-			current = newsize;
-		else {
-			Py_BEGIN_ALLOW_THREADS
-			errno = 0;
-			current = _portable_ftell(f->f_fp);
-			Py_END_ALLOW_THREADS
-			if (current == -1)
-				goto onioerror;
-		}
-
-		/* Move to newsize. */
-		if (current != newsize) {
-			Py_BEGIN_ALLOW_THREADS
-			errno = 0;
-			error = _portable_fseek(f->f_fp, newsize, SEEK_SET)
-				!= 0;
-			Py_END_ALLOW_THREADS
-			if (error)
-				goto onioerror;
-		}
-
-		/* Truncate.  Note that this may grow the file! */
-		Py_BEGIN_ALLOW_THREADS
-		errno = 0;
-		hFile = (HANDLE)_get_osfhandle(fileno(f->f_fp));
-		error = hFile == (HANDLE)-1;
-		if (!error) {
-			error = SetEndOfFile(hFile) == 0;
-			if (error)
-				errno = EACCES;
-		}
-		Py_END_ALLOW_THREADS
-		if (error)
-			goto onioerror;
-
-		/* Restore original file position. */
-		if (current != newsize) {
+	/* can use _chsize; if, however, the newsize overflows 32-bits then
+	   _chsize is *not* adequate; in this case, an OverflowError is raised */
+	if (newsize > LONG_MAX) {
+		PyErr_SetString(PyExc_OverflowError,
+			"the new size is too long for _chsize (it is limited to 32-bit values)");
+		return NULL;
+	} else {
 		Py_BEGIN_ALLOW_THREADS
 		errno = 0;
-			error = _portable_fseek(f->f_fp, current, SEEK_SET)
-				!= 0;
+		ret = _chsize(fileno(f->f_fp), (long)newsize);
 		Py_END_ALLOW_THREADS
-			if (error)
-				goto onioerror;
-		}
+		if (ret != 0) goto onioerror;
 	}
 #else
 	Py_BEGIN_ALLOW_THREADS